Abstract: The general theory of simple transport processes between quantum mechanical
reservoirs is reviewed and extended. We focus on thermoelectric phenomena,
involving exchange of energy and particles. Entropy production and Onsager
relations are relevant thermodynamic notions which are shown to emerge from the
microscopic description. The theory is illustrated on the example of two
reservoirs of free fermions coupled through a local interaction. We construct a
stationary state and determine energy- and particle currents with the help of a
convergent perturbation series.
We explicitly calculate several interesting quantities to lowest order, such
as the entropy production, the resistance, and the heat conductivity.
Convergence of the perturbation series allows us to prove that they are
strictly positive under suitable assumptions on the interaction between the
reservoirs.